Patterning Method for Carbon-Based Substrate

ABSTRACT

A patterning method for a carbon-based substrate is provided. The patterning method for the carbon-based substrate includes the following steps. The carbon-based substrate is provided. An atmospheric pressure plasma is produced from a plasma gas under an open air environment. The plasma gas includes oxygen. The carbon-based substrate is etched by the atmospheric pressure plasma.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a patterning method for a substrate,and more particularly to a patterning method for a carbon-basedsubstrate.

2. Description of the Related Art

The carbon-based substrate, having the features of high conductive, highstrength and high bendability, has attracted great attention in recentyears. The multi-touch effect can be achieved if a circuit pattern likea transistor array is marked on the carbon-based substrate so as to forma transparent carbon nanostructure-based thin film. The transparentcarbon nanostructure-based thin film, having achieved the standards of85% transmittance and 200 Ω/sq impedance, can be used in the touch panelof various electronic products.

The traditional IC processes use a photo resistor in a lithography stepand a wet etching step to form the circuit pattern. However, the stronganti-corrosion of the carbon-based substrate makes the manufacturingprocess thereof complicated and time-consuming. Thus, the manufacturingcost of the carbon-based substrate is hard to be reduced and thecarbon-based substrate cannot be widely used in various electronicproducts.

SUMMARY OF THE INVENTION

The invention is directed to a patterning method for a carbon-basedsubstrate. The carbon-based substrate is etched by an oxygen-containedplasma at an atmospheric pressure, so that the process of patterning thecarbon-based substrate is more efficient and more convenient.

According to a first aspect of the present invention, a patterningmethod for a carbon-based substrate is provided. The patterning methodfor the carbon-based substrate includes the following steps. Thecarbon-based substrate is provided. Under an open air environment, anatmospheric pressure plasma is produced from a plasma gas that includesmostly usually gas like oxygen, nitrogen, argon, clean dry air or mixedgas of them. The carbon-based substrate is etched by the atmosphericpressure plasma.

The invention will become apparent from the following detaileddescription of the preferred but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart of a patterning method for a carbon-basedsubstrate; and

FIGS. 2-7 respectively show the steps of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The invention is exemplified by an embodiment below. However, theembodiment is for exemplification only, not for limiting the scope ofprotection of the invention. Besides, secondary elements are omitted inthe embodiment for highlighting the technical features of the invention.

Referring to FIG. 1 and FIGS. 2-7. FIG. 1 shows a flowchart of apatterning method for a carbon-based substrate 100. FIGS. 2-7 show therespective steps of FIG. 1.

Firstly, the method begins at step S102, as indicated in FIG. 2, acarbon-based substrate 100 is provided. In the present embodiment of theinvention, the carbon-based substrate 100 is exemplified by atransparent carbon nanostructure-based thin film like carbon nanotube ornano-graphite. The optical properties of the transparent carbonnanostructure-based thin film are similar to that of the indium tinoxide film (ITO film). The transparent carbon nanostructure-based thinfilm having high electron conductivity can be used to form a conductivefilm with high transparency. Therefore, the transparent carbonnanostructure-based thin film can be used in electronic devices such asdisplays and solar batteries, which require a transparent electrode, orused in photo-electrical elements such as transistors and sensors.

Next, the method proceeds to step S104, as indicated in FIG. 3, a hardmask 300 is provided. The hard mask 300 has a hollowed pattern 310. Thehard mask 300 is made from metal, ceramic or glass. The hollowed pattern310 is a predetermined etching pattern of the carbon-based substrate100, wherein, the hollowed pattern 310 penetrates an upper surface 300 aand a lower surface 300 b of the hard mask 300, and an inner-sidewall310 a of the hollowed pattern 310 is a steep sidewall so that theatmospheric pressure plasma 500 (illustrated in FIG. 5) of thesubsequent step can conveniently penetrate through.

In step S104, the inner-sidewall 310 a of the hollowed pattern 310 is asteep sidewall; therefore, the hollowed pattern 310 of the hard mask 300can be formed by ways of mechanical or chemical process, such asmechanical cutting, laser cutting, knife cutting, electric dischargemachining or photo-etching.

Then, the method proceeds to step S106, as indicated in FIG. 4, the hardmask 300 is attached to the carbon-based substrate 100, wherein thehollowed pattern 310 exposes a portion of the carbon-based substrate100. Whether the hard mask 300 contacts the carbon-based substrate 100depends on the accuracy of the subsequent etching process. When the hardmask 300 contacts the carbon-based substrate 100, the hard mask 300 canbe fixed by a detachable adhesive (or a tape) or by a mechanical fixingelement.

As disclosed in steps S104 and S106, the material of the hard mask 300is not the patterned photoresist or the patterned silicon nitrideadopted in the semiconductor process. Moreover, the hard mask 300already forms the hollowed pattern 310 before, not after, being attachedto the carbon-based substrate 100.

Thus, after the etching process of the hollowed pattern 310 of the hardmask 300 is completed, the same hard mask 300 can be repeated used inseveral carbon-based substrates 100.

Afterwards, the method proceeds to step S108, as indicated in FIG. 5, anatmospheric pressure plasma 500 is produced from a plasma gas under anopen air environment such as an atmospheric pressure or close to anatmospheric pressure.

The atmospheric pressure plasma 500 has cost advantage. In terms ofequipment cost, the atmospheric pressure plasma 500 can do without theuse of expensive and clumsy vacuum equipment. During the manufacturingprocess, the to-be-processed object is not subjected to the vacuumcavity, and is thus applicable to continual process. These features allcontribute to reducing the manufacturing cost.

In terms of the components of the plasma gas for producing theatmospheric pressure plasma 500, the plasma gas at least includesoxygen, such as pure oxygen, mixed gas of nitrogen and oxygen, mixed gasof argon and oxygen and clean dry air (CDA).

In terms of the device for producing the atmospheric pressure plasma500, the atmospheric pressure plasma 500 is produced from an arc jetplasma generator or a nonthermal dielectric barrier discharges (DBD)plasma generator for example.

In terms of the form of the atmospheric pressure plasma 500, theatmospheric pressure plasma 500 is a dotted atmospheric pressure plasmaor a linear atmospheric pressure plasma for example.

Then, the method proceeds to step S110, as indicated in FIG. 6, thecarbon-based substrate is etched by the atmospheric pressure plasma 500.The etching process uses the hard mask 300 as a shield, and only theportion of the carbon-based substrate 100 exposed on the hollowedpattern 310 is etched.

As disclosed above, the atmospheric pressure plasma 500 of the presentembodiment of the invention is dotted or linear atmospheric pressureplasma. Thus, during the etching process, the carbon-based substrate 100is etched by the atmospheric pressure plasma 500 through scanning.

As the atmospheric pressure plasma 500 of the present embodiment of theinvention is produced from oxygen-based plasma gas, the atmosphericpressure plasma 500 contains oxygen plasma ions. When the oxygen plasmaions contact the carbon-based substrate 100, a chemical reaction isgenerated by oxygen ions and the carbon-based substrate 100 to form avaporizable air (such as carbon dioxide). The carbon-based substrate 100is etched by the chemical reaction. Thus, in the present embodiment ofthe invention, the etching between the atmospheric pressure plasma 500and the carbon-based substrate 100 is mainly done through a dry chemicalreaction rather than through a wet chemical reaction or an ionbombardment. Therefore, the etching method of the present embodiment ofthe invention has very high etching selectivity and very high etchingrate as well.

Then, the method proceeds to step S112, as indicated in FIG. 7, the hardmask 300 is removed form the carbon-based substrate 100. As the hardmask 300 is not removed by destructive methods, and the atmosphericpressure plasma 500 will not destroy the hard mask 300 either, the hardmask 300 can be repeatedly used in several steps of etching thecarbon-based substrate 100.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A patterning method for a carbon-based substrate, comprising:providing a carbon-based substrate; producing an atmospheric pressureplasma from a plasma gas under an open air environment, wherein theplasma gas comprises oxygen; and etching the carbon-based substrate bythe atmospheric pressure plasma.
 2. The patterning method according toclaim 1, wherein in the step of providing the carbon-based substrate,the carbon-based substrate is a transparent carbon nanostructure-basedthin film.
 3. The patterning method according to claim 1, wherein beforethe step of producing the atmospheric pressure plasma, the patterningmethod further comprises: providing a hard mask having a hollowedpattern; and attaching the hard mask to the carbon-based substrate,wherein the hollowed pattern exposes a portion of the carbon-basedsubstrate.
 4. The patterning method according to claim 3, wherein in thestep of providing the hard mask, the hard mask is made from metal,ceramic or glass.
 5. The patterning method according to claim 3, whereinin the step of providing the hard mask, the hollowed pattern is formedby way of a mechanical cutting.
 6. The patterning method according toclaim 3, wherein in the step of providing the hard mask, the hollowedpattern is formed by way of a laser cutting.
 7. The patterning methodaccording to claim 3, wherein after the step of etching the carbon-basedsubstrate, the patterning method further comprises: removing the hardmask from the carbon-based substrate.
 8. The patterning method accordingto claim 1, wherein in the step of producing the atmospheric pressureplasma, the plasma gas further comprises nitrogen.
 9. The patterningmethod according to claim 1, wherein in the step of producing theatmospheric pressure plasma, the plasma gas is a clean dry air (CDA).10. The patterning method according to claim 1, wherein in the step ofproducing the atmospheric pressure plasma, the atmospheric pressureplasma is produced from an arc jet plasma generator.
 11. The patterningmethod according to claim 1, wherein in the step of producing theatmospheric pressure plasma, the atmospheric pressure plasma is producedfrom a nonthermal dielectric barrier discharges (DBD) plasma generator.12. The patterning method according to claim 1, wherein in the step ofproducing the atmospheric pressure plasma, the atmospheric pressureplasma is a dotted plasma.
 13. The patterning method according to claim1, wherein in the step of producing the atmospheric pressure plasma, theatmospheric pressure plasma is a linear plasma.
 14. The patterningmethod according to claim 1, wherein in the step of etching thecarbon-based substrate, the atmospheric pressure plasma etches thecarbon-based substrate through scanning.
 15. The patterning methodaccording to claim 1, wherein in the step of etching the carbon-basedsubstrate, the atmospheric pressure plasma and the carbon-basedsubstrate generate a chemical reaction, so that a portion of thecarbon-based substrate contacting the atmospheric pressure plasma formsa vaporizable air.